Device for producing foam



June 9, 1936.

E. WALDSCHMIDT I 2,043,599

DEVICE FOR PRODUCING FOAM Filed Jan. 22, 1934 Inone device of this kind, air with a certain,

Patented June 9, 1936 PATENT oFF-lcn I 2.04am

nrzvron ron rnonucnva roan Erich Wald achmidt, Berlln-Charlottenlmrg, Germany, alsignor, by mane assignments, to Pyrene-Mlnimax Corporation, a corporation of Delaware Application January 22. 1934. sci-m No. 707,808

' In Germany Janna-r120. 1933 4 Claims. (oi. zency This invention relates to a device for creating and conducting foam -in a mechanical manner.

- amount of pressure in very fine streams, is led into a liquid capable of forming foam. In another the gas and the foam-forming liquid are introduced into a device in which an intensive turbulent mixture of these substances takes place creating the foam. This procees requires the use with another material produces-a suction effect by of power.

of machinery and a considerable consumption In another process the material which is mixed which the latter is sucked in.- This process operates at acomparatively low pressure, so that the production of the foam begins in the mixing chamber or just beyond it. Therefore the conducting conduit for the foam mixture must have a large cross-section in view of the high-frictional coefficient of the foam, which in the case of long conduits, greatly influences the cost of the apparatus and the installation.

In" accordance with another process, pumps are used which suck in the air and the foam-forming fluid and mix them in a mixing apparatus. In this case also, machines having a high power consumption are necessary. Furthermore since the formation of the foam takes place in the mixing apparatus the conducting conduits associated therewith also require large cross-sections.

In applying the present invention, condensed gas or liquefied gas, for instance, carbon dioinde,

is used, stored in the well known steelbottles as a source of gas and energy. Even when requiring the production of very considerable quantities of foam, only a few such bottles with condensed or liquefied gas are necessary.

To extinguish, for instance, the confiagaration of an oil-tanksof about 30 m. diameter about 100,000 liters of foam would be required. To adhere to the cited example of the carbon dioxide, the required quantity of gas would be only 6 botles, each of a capacity. of 30 kilos contents. An

lar element, placed within a liquid, which may be the foam-forming liquid itself, for complete evaporation or pre-heating.

Condensed or liquefied gases have a very high pressure. Therefore the mixture and conducting of the foam-forming substances towards the place of fire can bearranged-in pipes under high pressure, resulting, from a point of ecnonomy, in the very great advantage of permitting piping of rather small diameter to be used, because the gas and liquid mixture at the existent high pressure remains in its characteristic liquefied condition and consequently has a correspondingly low'frictional coeflicient. Previous to the flowing of the foam to the place of fire a certain release of the pressure of the gas and liquid mixture takes place, and thus the formation of the foam is effected, for instance,by a widening of the piping at or near its end. It is of particular advantage when using carbonic acid that this gas is absorbed strongly by water when under high pressure, thus resulting in a considerable reduction of volume. For the foam-formation, or its improvement, it is already known to employ suitably porous bodies, such as, for instance, cylindrical receptacles with insets of fibrous fabrics, wire-screens, Raschigrings or the like, which'may be arranged at the beginning of the foam-conduitat the injectoras well as at the other end, at the place of consumption, or both, at the beginning and at the end. a

The accompanying drawing represents a diagrammatic view, partly in section, one form of device in accordance with the invention.

a is a pressure-proof steel-bottle, provided with a discharge pipe b. The branch-pipe 0 leads tangentially into a cylindrical receptacle d, serving as duction of the pipe 0 into this receptacle has the purpose of throwing by centrifugal force against the wall of the receptacle any snow which might form, in order to eiiect an evaporation thereof at this point. From the bottom of this receptacle it leads a pipe e, the entrance-opening of which is situated at some distance from the bottom of the receptacle, in order to prevent any clogging up of the pipe by carbon dioxide snow which may have formed here. In place of the receptacle d a pipe-coil might be also used or in order to insure a complete evaporation of the liquefied gas; the latter may be allowed to-enter from below into a receptacle partly filled with water.

The exit-pipe e of the vaporizer leads to the injector I which has at its rear end a flange g for the .connecion of a water-pipe. The water may vaporizer or pre-heater. The tangential intromay be drawn inby the injector. At the discharge end, the injector is provided with a flange h for connecting the foam piping. The latter may contain, as above mentioned, a distributing element at the'beginning or at the end, or at both points. A concentrated foam-forming solution, which is mixed within the injectorchamber l with the water entering the same, aches the injector througha pipe i coming fro the receptacle k. A pipe m branches of! from the pipe e and this pipe m leads to the top-part of there:

ceptacle lcfor the foam-forming solution. This conduit is provided with a reduction-valve a, preventing an excess of pressure within the receptacle It. All the pressures prevailing in the receptacles (land It, as ,well as in the injectorchamber 1 and at the injector-exit, can be indicated at special gauges M NF, M and M Having thus described my said invention, what I claim to be protected by Letters Patent is:

1. In an-apparatus' of the class described, a container for a highly compressed gas, a vaporizing receptacle connected with said container for vaporizing the compressed gas, a container for a foam-forming solution, an injector-like .mixing chamber for said gas under pressure and said solution, a conduit for the vaporized gas extending between said vaporizing. receptacle and said mixing chamber, said conduit ending within acaaaoe 2. In anapparatus of the class described, a container for a highly compressed gas, a vaporizing receptacle connected with said container for vaporizing the compressed gas, a container for a foam- -forming solution, a mixing chamber 5 for said gas under pressure and-said solution, a conduit for the vaporized gas extending between said vapo rizlng receptacle and said mixing chamher, a connection from theup'per part of said container to said conduit, a reducing valve in'10 said connection, a'connection from the lower part tainer for a foam-forming ingredient, an injector device for mixing said gas and foam-form ingre- 20 1 dient, a conduit for said gas extending into the forward end of said injector device near the exhaust end thereof, an inlet for water in the rear part of said injector device, a supply pipe extending from saidcontainer for the foam-forming in- 25 gredient and opening into said injector device between said gas and water inlets, and a pipe leading from the exhaust end of said injector device adapted to convey the mixture therefrom for expansion at suitable points and the production 30 of foam thereat.

- 4. The combination claimed in claim 3 wherein theconduit for the gas extends into the forward end of said injector device and directs the gas through the exhaust end thereof. 35

ERICK WALDSCHMIDT. 

